In the info panel, we see the values for the darker area have good separation between channels. Unwinding the image into linear light we can estimate the actual exposure. As a matter of reference, the more ideal exposure is the darker area on the far right of the screen. In the example the OP posted, the screen exposure is nearly a stop between the darkest and lightest area. But more important is that the screen be very even in lighting, within a quarter of a stop, particularly around the subject/action.
I’m mostly going to talk about tracking markers, but just quickly, green screen is ideally “under exposed” by as much as a stop and a half. And when it comes to tracking markers and green/blue/black screen there is so much misinformation it is shocking. Unfortunately productions all too often shoot without a dedicated VFX supervisor on set, and “wing it” expecting to “fix it in post”.
GREEN SCREEN MARKER MOVIE
You can watch my first green screen movie here.Yes I definitely agree with Dave that this is a poorly lit and uneven screen, and that’s probably going to cause the greatest problems.
GREEN SCREEN MARKER HOW TO
A discussion of chroma keys and how to use the green screen in Windows Movie Maker will follow. Place your lighting in such a way that the subject does not cast a shadow on the green screen. You can substitute for natural light with flood lights such as the one I clipped to a cabinet door here. On a sunny day, the results were better because of the light streaming through the windows. The other drawback in my intro video was lack of lighting in general. In my setup, I had a bank of three lights above the island which were directly above me as I filmed, and I stuck the magenta light in the middle socket. Ideally, the magenta light would be behind and above the subject. To make a cheap magenta light, paint a light bulb with a magenta permanent marker.
GREEN SCREEN MARKER SKIN
The purpose of the magenta light is to offset the green reflection on skin and fuzzy textures. A lot of lighting on the subject can help, especially if you add magenta lighting on the subject. At that distance, skin and fuzzy textures (such as my hair) will pick up the green from the screen and you end up with a green halo around the subject in the final special effects editing (see the tail end of the video in step 1). Because of the kitchen island, the most distance I could get between myself and the screen was four feet. The biggest drawback I had in using my green screen was that I didn't have enough room to stand the ideal 10 feet in front of the screen. In the ideal setup, the subject will be ten feet away from the green screen with two flood lights lighting the green screen (placed behind the subject), and lots of light (including magenta) aimed at the subject separately from the green screen. Note: I cut the foam core slightly smaller than the poster boards around the edges so the boards would overlap a bit when put together. These will serve as ribbing for the mounted green screen (see images).
Glue the opposite side of the hook and loop tape to something stiff-such as hard foam or lightweight wood slats. Snip the side of the hook and loop tape that is glued to the panels to they can be taken apart and stacked. Thirdly, place all 6 (or more) panels together on a flat surface back-side-up and glue strips of hook and loop tape in a pattern that will unite all the panels into one large green screen. Each panel should fold up to the size of a single poster board. Secondly, make two small green screens by taping two panels together on the back side. You can use rubber cement or spray adhesive, and you may need to cut and piece together the foam core (as I did because they were a different dimension from the poster boards). The first step is to mount the poster boards onto foam core. I made a six-panel green screen that can be taken apart and stored in a closet using poster board mounted on foam core-both purchased at a Dollar Store for a total cost of about $12.
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